Preheat the oven to 350 degrees F (175 degrees C). Grease a baking sheet lightly with oil; spread soy beans on top.
Bake in the preheated oven until slightly browned, about 20 minutes.
Combine soy beans, peanuts, oyster sauce, tahini, and red pepper flakes in a food processor or blender. Blend into a fine paste. Place the paste in a container and add vinegar. Stir together. Cover and let stand until flavors meld, about 2 1/2 hours.
Heat chile oil in a large skillet over medium heat. Cook and stir chicken until nicely browned, 8 to 10 minutes.
Combine chicken and homemade miso in a large pot. Add water, lentils, carrots, spinach, and tomatoes. Bring to a boil. Reduce heat to low and stir in peanut butter, chicken bouillon, sage, and cumin. Cover and simmer for about 1 hour.